Slip over collar type centralizer



Jan. 8, 1963 L. KLUCK 3,072,195

SLIP OVER COLLAR TYPE CENTRALIZER Filed May 5, 1960 2 Sheets-Sheet 1 22 Fig.2

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Jan. 8, 1963 L. KLUCK SLIP OVER COLLAR TYPE CENTRALIZER 2 Sheets-Sheet 2 Filed May 3, 1960 IN VENTOR. 4mm BY Lou/Is K/uck 3,072,195- Patented Jan. 8, 1963 3,072,195 SLIP OVER CDLLAR TYPE CENTRAHZER Louis Kluclr, Box 1421, @tlessa, Tex. Filed May 3, 1960, Ser. No. 26,552 11 Qlahns. (Cl. 166-441) This invention relates to a novel and useful slip over collar type centralizer specifically adapted for centralizing the well casing in a well bore and comprises an improvement over the features of the centralizer disclosed in my co-pending application Serial No. 793,022, filed February 13, 1959'.

When it is desired to cement portions of a well bore, common practice includes the insertion of a casing string within the well bore and the subsequent introduction of cement slurry between the walls of the casing and the well bore. In some cases the cement is introduced to the area defined between the casing and the well bore from the top of the well and in other cases the cement slurry is first passed downward through the center of the casing to subsequently be forced upwardly under pressure between the casing and the well bore. During cementing operations, it is extremely important that the casing be maintained centrally disposed in the well bore. The most common type of centralizers utilized for maintaining the casing centrally disposed in the well bore during the cementing operations include upper and lower ring elements having a plurality of circumferentially spaced outwardly bowed leaf springs attached at their upper ends and at their lower ends to the upper and lower rings respectively. The rings to which the leaf springs are attached are slidable on the casing sections and therefore a means must be provided for maintaining the centralizers in fixed positions longitudinally of the casing sections. However, only one of the rings carrying the leaf springs may be fixedly secured to the casing sections inasmuch as the other ring of the centralizer must be capable of movement toward and away from the ring fixedly secured to the casing section in order that the leaf springs secured between the ring elements may flex outwardly and inwardly to compensate for varying diameters of the well bore. It would be a simple matter to provide a means on one of the rings for engagement with the casing section to which it is secured in order to prevent relative movement between that ring and the well casing section. However, the well casing sections are threadedly secured together at adjoining ends and the resultant joint includes a diametrically enlarged portion on the string of well casing. Although both of the rings of each of the centralizers could be inserted over the small end of each of the casing sections, the rings may not be slid over the larger end of the casing sections.

As heretofore set forth, one of the rings of the centralizers may be secured in fixed relation to the casing section disposed therethrough by any convenient manner such as a setscrew or the like if it is desired, however, positioning means such as setscrews have at times proven to be inadequate in securing the centralizers in fixed position longitudinally of a casing section.

It is therefore the main object of this invention to provide a centralizer of the type having a lower ring and an upper ring with one of the rings being formed of a plurality of arcuate sections which may be rigidly secured together when desired. In this manner, each of the centralizers may have one of the rings positioned about one casing section as it is lowered from the top of the well bore and the other ring section may be spread apart and passed over the joint between adjacent casing sections and subsequent ly have its sections fixedly secured together about the other casing section so that the joint between adjacent sections is disposed between the upper and lower ring elements of a single centralizer. In this manner, the diametrically enlarged joint between the casing section itself Will maintain the centralizer in position longitudinally of the casing assembly.

During the cementing operation it is highly desirable to remove as much of the mud cake from the walls of the well bore as possible so that the cement slurry may at least partially penetrate the walls of the well bore in order that a more effective cementing operation may be carried out.

It is therefore a further object of this invention to provide a means for creating a turbulent action of the cement slurry as it is introduced between the well bore and the casing in order that the swirling action of the cement slurry will remove a substantial amount of the mud cake clinging to the walls of the well bore.

A further object of this invention, in accordance with the immediately preceding object, is to provide agitators spaced longitudinally of the casing assembly provided with outwardly projecting and circumferentially spaced blades inclined relative to the longitudinal axis of the well bore so that a swirling action will be given to the cement slurry travelling through the space disposed between the casing and the walls of the well bore.

A still further object of this invention is to provide a centralizer having one sectional ring Whose sections may be conveniently and rigidly secured together to form a unitary ring in order that a centralizer of maximum strength is provided.

And a final object to be specifically enumerated herein is to provide a centralizer and agitator for a well casing assembly to be used in cementing operations which will conform to conventional forms of manufacture, be of simple construction and fool-proof in operation so as to provide devices which will be economically feasible, durable and highly effective in preforming the desired functions.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like numerals refer to like parts throughout, and in which:

FIGURE 1 is a side elevational view of a conventional form of well casing assembly used in cementing operations shown with the centralizers and agitators of the instant invention secured thereto;

FIGURE 2 is a perspective view of one of the centralizers on somewhat of an enlarged scale;

FIGURE 3 is a bottom plan view of the centralizer illustrated in FIGURE 2;

FIGURE 4 is a fragmentary vertical longitudinal sectional view on somewhat of an enlarged scale taken substantially upon the plane indicated by the section line 4-4? of FIGURE 3;

FIGURE 5 is a fragmentary enlarged transverse horizontal sectional view taken substantially upon the plane indicated by the section line 5-5 of FIGURE 2;

FIGURE 6 is a top plan view of one of the agitators illustrated in FIGURE 1 on somewhat of an enlarged scale; and

FIGURE 7 is a transverse vertical sectional view taken substantially upon a plane indicated by the section line 7-7 of FIGURE 6.

Referring now more specifically to the drawings the numeral 10 generally designates a ground formation in which there is formed a well bore 12. Disposed in the well bore 12 is a casing assembly generally referred to by the reference numeral 14 including a plurality of aligned and joined tubing sections each generally designated by the reference numeral 16. Each of the tubing sections in is provided with an externally threaded lower end portion 13 and an internally threaded diametrically enlarged upper end portion 24 Abridging each of the joints formed by the juncture of the end portions 18 and 20 of adjacent casing sections 16 is a centralizer generally referred to by the reference numeral 22. Each of the centralizers 22 includes an upper ring 24 and a lower ring generally referred to by the reference numeral 26. A plurality of outwardly bowed and circumferentially spaced leaf springs are disposed between the rings 24 and 26 and have their upper and lower ends secured to the upper and lower rings 24- and 26 re- 'spectively in any convenient manner such as by welding 30.

The lower ring 26 of each of the centralizers 22 comprises a plurality of arcuate segments generally referred to by the reference numeral 32. It will be noted, see FIGURE 2, in particular, that the arcuate segments 32 form a continuous ring when their adjoining end portions are disposed in abutting relation.

Each of the arcuate segments 32 has fixedly secured to one end portion an arcuate joining plate 34. The arcuate joining plates 34 are fixedly secured to the corresponding arcuate segments 32 in any convenient manner such as by welding and the joining plates 34 extend beyond the end of the segment to which they are secured to overlap the adjacent end of the adjoining segment 32 in readily releasable surface-to-surface contacting relation therewith.

The free end of each of the joining plates 34 is provided with a bore 36 and the overlapped portion of the adjoining segment 32 is provided with a bore 38 aligned with the bore 36. The innermost end of the bore 38 is provided with a counter-bore 40 and a rivet generally designated by the reference numeral 42 has its head portion 4-4 seated in the counterbore 4t) and the free end of a shank portion .46 peened over the outer surfaces of the corresponding joining plate 34 surrounding the bore 36 after passing through the latter as at 48 to fixedly secure adjacent arcuate segments 32 together.

It will be noted that one end of each of the arcuate segments 32 is provided with a projection 56 and that the adjacent end of the adjacent segment 32 is provided with a complementary recess 52 in which the projection 59 of the adjacent segment 32 is seated. It is also to be noted that each of the joining plates 34- overlaps the joint between cor-responding projections 56' and recesses 52.

With attention now directed to FIGURES 1 and 6 and 7, there will be seen an agitator generally designated by the reference numeral 54. The agitator 54 includes a mounting ring generally referred to by the reference numeral 56- having a plurality of circumferentially spaced, radially extending and inclined blades 58 secured thereto. The blades 58 are secured to the ring 56 in any convenient manner such as by welding 6t; and it will be noted that the blades 58 are inclined relative to the longitudinal axis of the casing 14. The ring 56 is slidably disposed on the casing 14 and a positioning ring generally referred to by the reference numeral 62 is provided for securing the agitator 54 in longitudinally adjusted positions on the casing 14. The positioning ring 62 includes a plurality of threaded bores 64 formed therethrough in which there are disposed setscrews 66. Lock nuts 63 are provided for retaining the setscrews 66 secured in the bores and in engagement with the casing sections 16.

Agitators 54 may either be slidably disposed on the casing sections 16 or they may be fixedly secured in any convenient manner to one of the positioning rings 62. Alternately, the agitators 54 may be fixedly secured to the upper ring element 24 of a centralizer 22 if desired, see FIGURE 1.

In operation, as the casing sections 16 and 18 are added at the top of the well bore 12 the centralizers 22 and the agitators 54 may be secured to the casing sections 16 in any of the methods herein described. After the casing assembly 14 has been properly positioned in the bore 12, the cement slurry may be introduced from either the top of the bore 12 or from the bottom of the casing 14. As

the cement slurry is forced through the area defined between the casing 14 and the walls of the well bore 12, the centralizers 22 will maintain the casing 14 centrally disposed in the well bore 12 and the agitators 54 will effect a swirling motion to the cement slurry which will in turn cleanse the walls of the bore 12 from any mud cake clinging thereto. The mud cake will then of course be carried to either the top of the well bore 12 or to the bottom of the casing 14 depending on the direction of the movement of the cement slur'ry through the area defined between the casing 14 and the walls of the well bore 12. Cleansing of the walls of the bore 12 eliminates the necessity of the use of scratchers which have a tendency to cause restriction of the area defined between the casing 14 and the bore 12. Elimination of possible restrictions in this area greatly decreases the possibility of the casing 14 splitting due to increased pump pressures necessary to circulate the cement slurry through restricted areas. Further, the removal of wall cake will also eliminate channeling of the cement caused by cake clinging to the walls of the well bore 12 and will also eliminate excessive contamination of the cement slurry.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention as claimed.

What is claimed as new is as follows:

1. A centralizer for a drill casing comprising upper and lower ring elements, a plurality of bowed leaf springs attached at their upper and lower ends to said upper and lower rings respectively, said lower ring including a plurality of arcuate segments, the lower end of at least one of said springs secured to each of said segments, readily releasable means interconnecting said segments, said interconnecting means including a plurality of arcuate joining plates, one end of each of said plates fixedly secured to the outer surface of an end of one of said segments with the other end of each plate overlapping the outer surface of the adjacent end of the adjacent segment in surface-to-surface contacting relation therewith, said segments being normally resiliently urged by said springs, upon engagement of their mid-portions with a wellbore, radially inwardly toward end abutting relation with said plates overlapping adjacent ends of said segments, and means rigidly securing the other ends of each of said plates to the overlapped portion of the adjacent segment.

2. The combination of claim 1 wherein adjacent ends of said segments are provided with interlocking projections and recesses.

3. The combination of claim 2 wherein said projections each form an arcuate continuation of the corresponding segment and said recesses each extend circumferentially of the corresponding segment.

4. The combination of claim 1 wherein the other end of each of said plates has a bore formed therethrough, the overlapped portion of the adjacent plate having a bore formed therein aligned with the bore formed in the corresponding plate, fasteners secured through said aligned bores.

5. The combination of claim 4 including a counter bore formed in the innermost end of each of said bores in said segments, said fasteners each having a head portion complementary to and recessed in one of said counter bores.

6. The combination of claim 1 including an agitator secured to said top ring, said agitator including a ring member, means securing said ring member to said top ring, a plurality of circumferentially spaced and radially extending blades secured to said ring member, each of said blades being inclined relative to the longitudinal axis of its ring member.

7. The combination of claim 1 including an agitator adapted to assist said leaf springs in preventing the formation of wall cake, and thereby eliminating the need for scratchers, said agitators comprising a ring member, a plurality of circumferentially spaced and radially extending blades secured to said ring member, a positioning ring secured to said ring member, each of said blades being inclined relative to the longitudinal axis of said ring member positioning ring carried by and aligned with said ring member, and means carried by said positioning ring for engagement with a well casing passing therethrough to position said agitators in a selected position longitudinally along said well casing.

8. A centralizer for a drill casing comprising upper and lower ring elements, a plurality of bowed leaf springs attached at their upper and lower ends to said upper and lower rings respectively, said lower ring including a plurality of arcuate segments, the lower end of at least one of said springs secured to each of said segments, readily releasable means interconnecting said segments, said interconnecting means including a plurality of arcuate joining p1ates,.one end of each of said plates fixedly secured to the outer surface of an end of one of said segments with the other end of each plate overlapping the outer surface of the adjacent end of the adjacent segment in surface to surface contacting relation therewith, said segments being normally resiliently, urged by said springs upon engagement of their mid-portions with a wellbore, radially inwardly toward end abutting relation with said plates overlapping adjacent ends of said segments, the adjacent ends of said segments being provided with interlocking projections and recesses, said projections each forming an arcuate continuation of the corresponding segment and said recesses each extending circumferentially of the corresponding segment, said projections and recesses being formed in said segments intermediate their upper and lower surfaces, said plates each overlapping the corresponding projections and recesses.

9. A well casing string section for facilitating a cementing operation, said casing string section comprising a plurality of elongated tubing sections each including a first externally threaded end portion on one end and a second internally threaded diametrically enlarged end portion on the other end, said tubing sections being secured together in longitudinal alignment with the one end of each threadedly engaged in the other end of an adjacent section, a plurality of centralizers positioned at spaced integrals along said string casing section, each of said centralizers including first and second spaced ring elements slidably disposed on said casing assembly, a plurality of outwardly bowed leaf springs attached at their opposite ends to said first and second rings respectively, said second ring including a plurality of arcuate segments, the adjacent end of at least one of said springs secured to each of said segments, detachable means interconnecting said segments, said interconnecting means including a plurality of arcuate joining plates, one end of each of said plates fixedly secured to the outer surface of an end of a corresponding one of said segments and the other end of each plate overlapping the outer surface of the adjacent end of the adjacent segment in surface to surface contacting relation therewith, said first ring of each centralizer being disposed about one of said first end portions and second ring of that centralizer being removably secured about the adjacent end of the adjacent tubing section with the rings of each centralizer disposed on opposite sides of the corresponding diametrically enlarged end portions of the tubing sections.

10. The combination of claim 9, including an agitator secured to said first ring, said agitator including a ring member, means securing said ring member to said first ring, a plurality of circumferentially spaced and radially extending blades secured to said ring member, each of said blades being inclined relative to the longitudinal axis of its ring member.

11. The combination of claim 10, including a plurality of agitators, each of said agitators comprising a ring member slidably disposed on one of said tubing sections, means on each of said ring members for engagement with the corresponding tubing section to position said ring member longitudinally therealong, a plurality of circumferentially spaced and radially extending blades secured to said ring member, each of said blades being inclined relative to the longitudinal axis of its ring member.

, References Cited in the file of this patent UNITED STATES PATENTS 1,460,632 Wigle et a1 July 3, 1923 2,312,600 Steps Mar. 2, 1943 2,628,682 Wright Feb. 17, 1953 2,665,762 Althouse Jan. 12, 1954 2,860,013 Medearis Nov. 11, 1958 

1. A CENTRALIZER FOR A DRILL CASING COMPRISING UPPER AND LOWER RING ELEMENTS, A PLURALITY OF BOWED LEAF SPRINGS ATTACHED AT THEIR UPPER AND LOWER ENDS TO SAID UPPER AND LOWER RINGS RESPECTIVELY, SAID LOWER RING INCLUDING A PLURALITY OF ARCUATE SEGMENTS, THE LOWER END OF AT LEAST ONE OF SAID SPRINGS SECURED TO EACH OF SAID SEGMENTS, READILY RELEASABLE MEANS INTERCONNECTING SAID SEGMENTS, SAID INTERCONNECTING MEANS INCLUDING A PLURALITY OF ARCUATE JOINING PLATES, ONE END OF EACH OF SAID PLATES FIXEDLY SECURED TO THE OUTER SURFACE OF AN END OF ONE OF SAID SEGMENTS WITH THE OTHER END OF EACH PLATE OVERLAPPING THE OUTER SURFACE OF THE ADJACENT END OF THE ADJACENT SEGMENT IN SURFACE-TO-SURFACE CONTACTING RELATION THEREWITH, SAID SEGMENTS BEING NORMALLY RESILIENTLY URGED BY SAID SPRINGS, UPON ENGAGEMENT OF THEIR MID-PORTIONS WITH A WELLBORE, RADIALLY INWARDLY TOWARD END ABUTTING RELATION WITH SAID PLATES OVERLAPPING ADJACENT ENDS OF SAID SEGMENTS, AND MEANS RIGIDLY SECURING THE OTHER ENDS OF EACH OF SAID PLATES TO THE OVERLAPPED PORTION OF THE ADJACENT SEGMENT. 